A series of 122 phase BaFe2−xNixAs2 (x = 0, 0.055, 0.096, 0.18 and 0.23) single crystals was grown by the self-flux method and a dome-like Ni doping dependence of the superconducting transition temperature was discovered. The transition temperature T on c reaches a maximum of 20.5K at x = 0.096, and it drops to below 4K as x > 0.23. The negative thermopower in the normal state indicates that th...

We study alkali-metal adsorption on supported graphene by means of density-functional-theory calculations that include dispersion corrections. Graphene supported by the Au/Ni(111) surface is an important system for fundamental studies because this surface allows one to support graphene, preserving the electronic properties of freestanding graphene. We investigate the binding energetics as well ...

The chemical selectivity and great sensitivity of the Extended X-ray Absorption Spectroscopy technique allowed the determination, in the paramagnetic phase, of the structural distortions induced by doping in the spin-Peierls CuGeO3 compound. The distorted environments were analyzed as a function of concentration, magnetic nature of impurity and the substitution site (Ni, Mn and Zn impurities on...

In perovskites, exsolution of transition metals has been proposed as a smart catalyst design for energy applications. Although there exist transition metals with superior catalytic activity, they are limited by their ability to exsolve under a reducing environment. When a doping element is present in the perovskite, it is often observed that the surface segregation of the doping element is chan...

Temperature-dependent interplane resistivity ρc(T ) was measured systematically as a function of transitionmetal substitution in the iron-arsenide superconductors Ba(Fe1−xMx)2As2, M = Ni, Pd, Rh. The data are compared with the behavior found in Ba(Fe1−xCox)2As2, revealing resistive signatures of pseudogap. In all compounds we find resistivity crossover at a characteristic pseudogap temperature ...

The effect of Ni doping (1%, 2%, and 5%) on vanadium phosphate catalysts prepared via VOPO4·2H2O was described and discussed. At low levels, the Ni dopant significantly enhanced the amount of the active lattice oxygen species O− and lowered the reduction peak temperature corresponding to the reduction of V5+ and V4+ phases. A combination of powder X-ray diffraction, temperature-programmed reduc...

Both magnetic-field-induced reverse martensitic transformation (MFIRMT) and mechanical properties are crucial for application of Ni-Mn-Sn magnetic shape memory alloys. Here, we demonstrate that substitution of Fe for Ni can simultaneously enhance the MFIRMT and mechanical properties of Ni-Mn-Sn, which are advantageous for its applications. The austenite in Ni44Fe6Mn39Sn11 shows the typical ferr...

Doping with other elements is one of the efficient ways to modify the physical and chemical properties of TiO2 nanomaterials. In the present work, Ni-doped TiO2 nanotubes were fabricated through anodic oxidation of NiTi alloy and further annealing treatment. The hydrogen sensing properties of the nanotube sensor were investigated. It was found that the Ni-doped TiO2 nanotubes were sensitive to ...

The oxidation kinetics of 5 vol% nano-Ni dispersed Al2O3 with Si-doping (nano-Ni/Al2O3-Si) was studied in the present paper. The starting powder mixture was prepared by drying aqueous slurry consisting of alumina with nickel nitrate and Si (OCH3)4. The powder mixture was reduced at 600 C for 12 h in a stream of Ar-1%H2 gas mixture. Nano-Ni/Al2O3-Si was densified by pulsed electric current sinte...

Nanostructured Ni-doped skutterudites Co(1-x)Ni(x)Sb3 (with x ranging from 0.01 to 0.09) were prepared by ball milling and direct-current induced hot press. It was found that the thermal conductivity was reduced due to strong electron-phonon scattering from Ni-doping as well as phonon scattering from the increased grain boundary of the nanostructures. A maximum dimensionless figure-of-merit of ...